In a wide variety of applications wherein materials of one form or another are loaded, packaged and/or shipped it is desirable to provide structural reinforcement to the packaging assembly which may desirably include a degree of protection such as cushioning of the packaged load. In other applications it is desirable to provide a relatively rigid and warp-free paperboard member for constructing articles of relatively light weight and low cost which nevertheless possess the high strength and rigidity necessary for that particular application.
For example, in the shipment of a wide variety of materials and articles of manufacture, a pallet load of material often is accumulated and placed on a wooden skid or pallet such that it may be picked up and moved by a standard forklift truck. The load is secured to the pallet by means of tensioned high strength steel or plastic strapping passing over the load and down around the pallet. Material which is shipped in this manner spans a gamut from fine paper to printed products, such as newspapers, advertising inserts, and magazines, to boxed, cartoned or otherwise packaged goods, such as bottles, cans, and boxes. The range of different goods and applications handled in this manner is virtually limitless. In each case the load must be protected both from the force of the tensioned strapping itself passing over the edges of the load and damage from knocking, denting and abrasion with adjacent loads or with the truck or railroad car in which the load is shipped.
Protection of the load has been provided in the prior art by forming a wooden frame having a length and width generally corresponding to the length and width of the skid. The wooden frame is placed on the top of the load and the strapping passed over the edges. The use of wood has a number of disadvantages including the accumulation of dirt and the presence of moisture which can transfer to the load. Moreover, wood is heavy increasing the shipping weight, bulky taking into consideration room to store, unwielding making it hard to handle, and expensive. Further, the wood frames do not provide complete protection to the top of the load; and, even where a separate sheet or moisture barrier material is provided to protect the top of the load, provides no protection whatever to the sides of the load at the top edges.
Some shippers have substituted the use of rigid preformed paperboard angles for the wood frames. In this application, laminated paperboard which is glued, treated and formed into rigid right angles is either glued or stapled onto a frame which fits down around the top of the skid load. The single sheet of paperboard may be interposed between this frame and the top of the load to provide protection to the top of the load. The strapping is then passed over the right angle to secure the load to the skid. This particular form of corner protection has advantages over the use of a wood frame in that it cushions the load edges against hard knocks and strap indentation, replaces expensive lumber, and provides for some protection to the top edge of the load. On the other hand, the use of paperboard angles has a number of disadvantages in that additional labor is required to form the angles into a frame and handling problems are encountered in the moving and placing of that frame about the top of the skid load. All in all such angles are relatively unwielding to assemble and to place on the load and require additional labor.
In another application, it is often desired to protect the edges of a product which is inserted into a carton or strapped with bands. For example, in the shipment of doors it is desired to provide the side and top and bottom edges with protection extending about the edges and onto the opposing faces of the door such that straps do not cut into the edges. In this application is often desired to have a relatively high strength material protecting the door edges. Sheets of corrugated cardboard have been used in the past. However, that material is not of the desired requisite strength and is subject to crushing by the bands passing around the edges of the door.
In another application, it is desired to wrap a product, such as coils of wire or metal or bundles of rods, with a layer of wrapping to protect the exposed surfaces thereof but in addition to provide a strong, compression-resistant cover over the surface thereof.
In summary, there are a number of applications where it is desired to provide a high strength warp-free structural member having a high degree of rigidity and compression resistance which is nevertheless easy to manufacture and relatively inexpensive to produce.